1. Set a large, heavy-bottomed skillet over medium heat and cook the sausage, breaking it up with a wooden spoon, until it is loose and no longer pink, approximately 10 minutes. Taste sausage and adjust seasonings — you may wish to add sage and fennel aggressively.
2. Sprinkle the flour and pepper over the sausage and cook, stirring constantly, until the flour has been absorbed by the fat and has gathered its flavors close, approximately 2 to 5 minutes.
3. Slowly stir in the milk and cook at a bare simmer until the gravy gets thick and the roux covers the back of a spoon. If it is too thick for your liking add more milk and stir. Check seasonings and serve over split or roughly crumbled biscuits.